The effect of the hydric deficit, by omitting one irrigation, at different stages of development of common-bean (Phaseolug vulagaris L., Huetar cultivar) was studied from January 31 st through April 18 th, 1986, at the Fabio Baudrit Experimental Station in Alaiuela, Costa Rica. A Ramdomized Complete Block Design with six treatments and four replications was used. The experimental unit consisted of three 40 m long rows, planted 0.60 m apart, and taking the intermediate row as the useful plot (22.8 m2). The treatments consisted in the omission of one irrigation during the following deve1opment stages (according to the nomenclature of the Centro Internacional de Agricultura Tropical- CIAT, 1983) a) appearance of the first trifoliate leaf, b) pre-blooming, c) blooming, d)pod filling, e) maturation and f) control with no water restrain. There were significant differences among treatments in seed production at 12 %,humidity and number of pods-per plant. The lowest yields in seed production and number of pods per plant were produced when the water was withheld at the blooming and pod filling stages.